In wake of the incident of
the "Spies,"
in which the generation that came out of Egypt under Moses' leadership demonstrated their unpreparedness for the task of conquering and settling the Holy Land, G-d decreed that entire generation would die out in the desert (see "Today in Jewish History" for Av 8 and Av 9). After 38 years of wandering through the wilderness the dying finally ended, and a new generation of Jews stood ready to enter the Holy Land. It was the 15th of Av of the year 2487 from creation (1274 BCE)

In order to ensure the orderly division of the Holy Land between the twelve tribes of Israel, restrictions had been placed on marriages between members of two different tribes. A woman who had inherited tribal lands from her father was forbidden to marry out of her tribe, lest her children -- members of their father's tribe -- cause the transfer of land from one tribe to another by inheriting her estate (Number 36). This ordinance was binding only on the generation that conquered and settled the Holy Land during the 14-year period 2488-2503 from creation (1273-1258 BCE); when the restriction was lifted, on the 15th of Av, the event was considered a cause for celebration and festivity.

Av 15 was the day on which the tribe of Benjamin, which had been excommunicated for its behavior in the incident of the
"Concubine at Givah," was readmitted into the community of Israel (as related in Judges 19-21). The event occurred during the judgeship of Othniel ben Knaz, who led the people of Israel in the years 2533-2573 from creation (1228-1188 BCE).

Upon the division of the Holy Land into two kingdoms following the death of King Solomon in the year 2964 from creation (797 BCE), Jeroboam ben Nebat, ruler of the breakaway Northern Kingdom of Israel, set up roadblocks to prevent his citizens from making the thrice-yearly pilgrimage to the Holy Temple in Jerusalem, capital of the Southern Kingdom of Judea. These were finally removed more than 200 years later by Hosea ben Eilah, the last king of the Northern Kingdom, on Av 15, 3187 (574 BCE).

The fortress of Betar was the last holdout of
the Bar Kochba rebellion. When Betar fell on the 9th of Av, 3893 (133 CE), Bar Kochba and many thousands of Jews were killed; the Romans massacred the survivors of the battle with great cruelty and would not even allow the Jews to bury their dead. For 15 years their remains were left scattered on the battlefield. When the dead of Betar were finally brought to burial on Av 15 of the year 3908 from creation (148 CE), an additional blessing (HaTov VehaMeitiv) was added to the "Grace After Meals" in commemoration.

In ancient Israel, it was the custom that on the 15th of Av "the daughters of Jerusalem would go out in borrowed linen garments (so as not to embarrass those without beautiful clothes of their own)... and dance in the vineyards" and "whoever did not have a wife would go there" to find himself a bride (Talmud, Taanit 31a).

When the Holy Temple stood in Jerusalem, the annual cutting of firewood for the altar was concluded on the 15th of Av.
The event was celebrated with feasting and rejoicing, as is the custom upon the conclusion of a holy endeavor, and included a ceremonial breaking of the axes which gave the day its name.

Because of the joyous events which occurred on this day (see "Today in Jewish History"), our sages regarded the 15th of Av to be one of the two most auspicious days on the Jewish calendar (the other being Yom Kippur--Talmud, Taanit 26b). Nevertheless, no special Av 15 observances or celebrations are ordained by Halachah (Torah law) or custom, other than the omission of the tachnun (confession of sins) and similar portions from the daily prayers, as is the case with all festive dates.